#2 was a joke, gentlemen. The whole thing sounds kinda iffy to me, but perhaps there would be some merit in having a handgun that you could punch people with. But it'd mainly come down to whether the need for that feature was statistically probable enough to warrant doing the engineering.

I'm mostly of the opinion that it'd be like engineering a pen that can write upside down, in space; why not just use a pencil?

Well, joking aside, I'd invest some dollars in that if I could be convinced it was tacticool enough for gun fetishists to buy that I'd get a return on my investment. I asked my gun enthusiast brother about the idea yesterday, and his response was "well, the guy that figured out you can attach a laser to a rail probably made a fortune." There's even a market for those pistol bayonets like BearHammer posted (I have no idea who's buying them).

While it wouldn't be proof against an impact related malfunction, I think that something like an extended threaded barrel with a thread protector would make a thrust with the barrel less likely to induce slide movement.

I'd be shocked if some company doesn't have a thread protector with crenelations for handguns out for sale already. Impact muzzle devices are easy enough to find for shotguns and rifles.